The international standard, a cylinder-shaped hunk of metal that defines the fundamental unit of mass, has gained tens of micrograms in weight from surface contamination, according to a new study.

If it's the international standard, then any increased or decreased mass becomes the new standard, by definition. If we perceive the standard as being wrong and it needs to be cleaned so that it's reduced to our expected amount of mass, it sounds like our expectation is more the true standard than the cylinder.

Lumpmoose:The international standard, a cylinder-shaped hunk of metal that defines the fundamental unit of mass, has gained tens of micrograms in weight from surface contamination, according to a new study.

If it's the international standard, then any increased or decreased mass becomes the new standard, by definition. If we perceive the standard as being wrong and it needs to be cleaned so that it's reduced to our expected amount of mass, it sounds like our expectation is more the true standard than the cylinder.

No. If it's the international standard, it should remain constant. Having contamination means that it needs to be cleaned so that it can get back to being what it's supposed to be. No different than a white shirt getting dirty. Have your wife clean that so that it's white again.

ronaprhys:Lumpmoose: The international standard, a cylinder-shaped hunk of metal that defines the fundamental unit of mass, has gained tens of micrograms in weight from surface contamination, according to a new study.

If it's the international standard, then any increased or decreased mass becomes the new standard, by definition. If we perceive the standard as being wrong and it needs to be cleaned so that it's reduced to our expected amount of mass, it sounds like our expectation is more the true standard than the cylinder.

No. If it's the international standard, it should remain constant. Having contamination means that it needs to be cleaned so that it can get back to being what it's supposed to be. No different than a white shirt getting dirty. Have your wife clean that so that it's white again.

I thought they changed the kilogram standard to the most perfect sphere created by man to date, made out of a perfect silicon crystal lattice? Was this never officially adopted? Wouldn't solve the problem of people leaving traces of their grubby mitts on it, just curious and too lazy to look it up...

Pfighting Polish:Yes please: "The cylinder, which weighs approximately 2.2 pounds (1 kilogram), is the definition of the kilogram."

I saw this myself. Ever notice that, in college, the journalism/comm school tends to have the least intelligent people?

While journalists are typically not the most scientifically literate, the sentence is not incorrect. She didn't write that a kilogram is defined as 2.2 lbs., she noted that a kilogram weighs 2.2. lbs. Though to be most rigorous, she could've written that it weighs 2.2 lbs on Earth.

JustMatt:I thought they changed the kilogram standard to the most perfect sphere created by man to date, made out of a perfect silicon crystal lattice? Was this never officially adopted? Wouldn't solve the problem of people leaving traces of their grubby mitts on it, just curious and too lazy to look it up...

JustMatt:I thought they changed the kilogram standard to the most perfect sphere created by man to date, made out of a perfect silicon crystal lattice? Was this never officially adopted? Wouldn't solve the problem of people leaving traces of their grubby mitts on it, just curious and too lazy to look it up...

It's called the Avogadro project. It's under consideration, but hasn't been taken to committee since they haven't determined if it will be more stable in the long term than the current standard. There are other proposals as well to try and move away from a physical artifact as the standard. The generally favored ones are to define the kilogram in terms of the Planck constant, but that's on hold until 2014, according to wikipedia.

TofuTheAlmighty:While journalists are typically not the most scientifically literate, the sentence is not incorrect. She didn't write that a kilogram is defined as 2.2 lbs., she noted that a kilogram weighs 2.2. lbs. Though to be most rigorous, she could've written that it weighs 2.2 lbs on Earth.

The issue I take is that, in translating the weight of a kilogram to pounds, she also felt the need to translate it back to metric in parenthesis. Take out the pounds part and, oh, a kilogram is the equivalent of a kilogram? Really.

By this standard, I bet the article only goes out of the house on mornings when she doesn't take a shower, because she gets stuck in there for hours when she reads "Lather, rinse, repeat."

Pfighting Polish:TofuTheAlmighty: By this standard, I bet the article only goes out of the house on mornings when she doesn't take a shower, because she gets stuck in there for hours when she reads "Lather, rinse, repeat."

TofuTheAlmighty:Pfighting Polish: Yes please: "The cylinder, which weighs approximately 2.2 pounds (1 kilogram), is the definition of the kilogram."

I saw this myself. Ever notice that, in college, the journalism/comm school tends to have the least intelligent people?

While journalists are typically not the most scientifically literate, the sentence is not incorrect. She didn't write that a kilogram is defined as 2.2 lbs., she noted that a kilogram weighs 2.2. lbs. Though to be most rigorous, she could've written that it weighs 2.2 lbs on Earth.

Perhaps he was referring to the line after 2.2 pounds: "(1 kilogram) is the definition of the kilogram."

palan:JustMatt: I thought they changed the kilogram standard to the most perfect sphere created by man to date, made out of a perfect silicon crystal lattice? Was this never officially adopted? Wouldn't solve the problem of people leaving traces of their grubby mitts on it, just curious and too lazy to look it up...

It's called the Avogadro project. It's under consideration, but hasn't been taken to committee since they haven't determined if it will be more stable in the long term than the current standard. There are other proposals as well to try and move away from a physical artifact as the standard. The generally favored ones are to define the kilogram in terms of the Planck constant, but that's on hold until 2014, according to wikipedia.

Pfighting Polish:Pfighting Polish: TofuTheAlmighty: By this standard, I bet the article only goes out of the house on mornings when she doesn't take a shower, because she gets stuck in there for hours when she reads "Lather, rinse, repeat."

Atomgirl:"Long-term, however, most scientists want to get away from defining the kilogram based on a hunk of metal."

It appears this artcile was written with the assumption that a kilo is an arbitrary measure. But isn't a kilogram determined by the weight of a liter of water?

The gram (not kilogram) was determined by a cube of water in the 1800's. it changed because the weight can vary by temperature, pressure and composition. Since the weight is determined by the isotopes composing the water was deemed problematic and tried to find a stable artifact to base the mass on, leading to the weight they used.

abhorrent1:Can't they keep it somewhere where it won't get surface contamination? Clean room or something?

Came here to ask the same. I was thinking vacuum container inside a sealed red-light clean room, weighed and observed via the console in an adjacent clean room, with the whole thing inside an underground vault.

Unless the whole concept of a platinum-iridium reference weight just isn't that important, in which case keeping it in a glass jar is fine. Industrial scale manufacturers probably have a pretty good idea of how to make their own accurate kilogram. 1000ml of 4°C distilled water at sea level... or something.

Sim Tree:TofuTheAlmighty: Pfighting Polish: Yes please: "The cylinder, which weighs approximately 2.2 pounds (1 kilogram), is the definition of the kilogram."

I saw this myself. Ever notice that, in college, the journalism/comm school tends to have the least intelligent people?

While journalists are typically not the most scientifically literate, the sentence is not incorrect. She didn't write that a kilogram is defined as 2.2 lbs., she noted that a kilogram weighs 2.2. lbs. Though to be most rigorous, she could've written that it weighs 2.2 lbs on Earth.

Perhaps he was referring to the line after 2.2 pounds: "(1 kilogram) is the definition of the kilogram."

It's just poorly written in general. I'm sure the editor added the (1 kilogram) because that's what their editorial standard demands, not because it makes any sense or is necessary in any way. I'm half surprised they didn't say (2.2 pounds) after every mention of the word kilogram throughout the article.

Karac:The IPKs are stored in filtered laboratory air at constant temperature and pressure, but there's no way to completely isolate them from air pollution and contamination, Cumpson told LiveScience.

Couldn't you cut down on the air pollution by sucking all the air out of their storage environment? After all, how often can these things get used?

Vacuums cause outgassing of materials they come in contact with (think of how water boils easier at lower pressures). This vapor could then settle on the object. So you'd have to really clean the storage container, which is harder than cleaning the object itself and filtering the air.